Giving the fact that DM and HP infection synergistically elevate the risk of GC and the ability of metformin to suppress the methylation of PTEN, we hypothesized that DM may strengthen the tumorigenic effect of HP by promoting PTEN promoter methylation, and the administration of metformin may reduce the risk of GC by suppressing PTEN promoter methylation.23, 24, 25. The gene discussed is PTEN; the disease is diabetes mellitus.